The invention relates to a seat belt buckle comprising a release button for a latch slidably mounted on a frame, and an ejector for an insert tongue.
Known from DE 296 13 690 is one such buckle provided with a balance weight to prevent the release button from shifting out of place relative to the buckle when exposed to a heavy acceleration or deceleration in the longitudinal direction of the buckle due to its mass inertia and thus opening the buckle unintentionally. Inspite of this, unintentional opening may occur with this type of buckle when, for instance, the buckle is heavily accelerated by a belt tensioner and then abruptly decelerated on impacting a stopper. Since the belt tensioner has a certain clearance with respect to the release button it still has an impulse when the release button is already at rest. Since, however, the ejector needs to be mechanically coupled to the release button so that it is able to activate the latch on insertion of the insert tongue, this impulse is passed on via the ejector to the release button. At the point in time of impulse transfer, however, the compensation of the inertia by the balancing weight is no longer effective, since this is likewise at rest. When the impulse transmitted is sufficiently large there is thus the risk of the release button being shifted out of place, thus opening the buckle.
The invention provides a seat belt buckle in which with the insert tongue inserted any impulse transfer from the insert tongue to the release button is reliably prevented.
This is achieved with a seat belt buckle comprising a release button for a latch slidably mounted on a frame, an ejector for an insert tongue and at least one connecting element, the connecting element being shiftable between a working position, in which it makes a connection between the ejector and the release button, and a resting position in which it breaks the connection between the ejector and release button, a dislocator being provided on the frame which dislocates the connecting element from the resting position into the working position when the ejector is shifted out of place. Coupling only takes place when necessary, namely on insertion of the insert tongue, thus reliably preventing any impulse transfer from the insert tongue to the release button with the insert tongue inserted.
In accordance with the preferred embodiment of the invention the connecting element consists of a shifter formed on the ejector, and the dislocator is configured as a ramp on the frame on which the shifter slides when the ejector is shifted out of place and the length of the ramp is selected so that at the end of the shifting travel of the ejector the shifter is released from the ramp to fall back into its resting position. Compared to conventional buckles, this embodiment provides the advantage that no additional components are required. Only the configuration of two components, namely frame and ejector, needs to be modified.